Device having a thread tensioner for weaving shuttles for threading weft threads



Aug. 27, 1968 E.'FoR'sTER 3,393,756

DEVICE HAVING A THREAD TENSIONER FOR WEAVING SHUTTLES FOR THREADING WEFT THREADS Inra/w04 fm'/ Fnsrff Aug. 27, 1968 E. FoRsrx-:R 3,398,766

DEVICE HAVING A THREAD TENSIONER FOR WEAVING SHUTTLES FOR THREADING WEFT v'IHRILDS Filed June 29, 1965 www 2 Sheets-Sheet 2 United States Patent O DEVICE HAVING A THREAD 'I'ENSIONER FOR WEAVING SHUTTLES FOR THREADING WEFT THREADS Emil Forster, Hinwil, near Zurich, Switzerland, assignor to Firm Emil Forster A.G., Hinwil, near Zurich, Switzerland Filed June 29, 1965, Ser. No. 468,012 Claims priority, application Germany, July 4, 1964,

F 43,338; June 5, 1965, F 46,257

1 Claim. (Cl. 139-217) ABSTRACT F THE DISCLOSURE The invention provides a thread tensioning device for a weft thread shuttle where the carrying body is made of two parts with cheeks having opposite recesses, each having an enlarged portion proximate the cheek, and with brake jaws having a box-shaped member and an elastic intermediate member, one portion of which is encompassed -by the box-shaped -member an'd another portion which extends into the recess, while the boxshaped mem-ber is received in the enlarged portion.

Backgronnd of the invention The invention relates to weaving shuttles and is particularly concerned with a device equipped for tensioning the thread in weaving shuttles for the placing or weaving of weft threads.

Experience had in practice with known threading and tensioning devices has shown that they are no longer capable of coping with the increased requirements of high-speed weaving looms. rThis is especially cumbersome when silk or synthetic materials are being woven.

Speeding up `and braking of the shuttle produces oscillation impulses of the entire threading device, as well as also of the spring biased brake jaws. The development of such oscillation impulses is rfavored by the fact that the weight of the threading ydevices is chosen to be as small as possible. Frequently the threading devices are in the form of bodies presenting large surfaces made of thin sheet metal and Iwhich moreover are only secured to the weaving shuttle `body in one place. The braking jaws of the thread tensioning devices are likewise made to the smallest possible dimensions because of the weight involved. For that -reason a specilically high pressure is applied to the thread. The oscillations of the brake jaws, the development of which is enhanced at any rate by the springs, are suppressed only very little by the small guide surfaces in the jaws. The flapping or wobbling of the thread is a further cause of oscillations for the brake jaws as it develops when the thread runs oli of the weft thread carrier ywhich permits the thread to run between the brake jaws in continuously changing direction. Accordingly, there exist two systems capable of oscillation in threading devices that have lmeans rfor tensioning the thread, the oscillations of which may under certain conditions be additive. Disadvantageous consequences of these shortcomings are loose wefts, markings on the surface of the thread which are visible later on in the fabric, and tearing of the thread.

Summary of the invention IIn order to eliminate these shortcomings, it is an object of the invention to provide a threading device with thread tensioning means which is light in weight and economical to produce, whch can lbe readily assembled and easily installed, and at the same time is so dimensioned that the inherent oscillations which adversely affect the operation are prevented. At the same time, it is furthermore desirice able that the brake jaws have braking `surfaces that are as large as possible, `which are iloating but free of uttering, are received in elastic intermediate members that function in different ways and which are resilient, but possess great self-squelching qualites.

In accordance with the invention this problem is solved by a supporting body made of plastic mate-rial divided at the bridging member of the jaws, -and by box-shaped braking jaws which receive elastic intermedi-ate members that project outwardly, as well as by wear-resistant lining of the thread guides.

The adjustment of the braking force is made possible in that at least one of the elastic intermediate members engages a pressure plate which is adjustably arranged in the carrying body.

A parting or dividing of the carrying body which is particularly advantageous for the Iassembly and setting is obtained when the separating gap of the carrying body extends in the plane of a cheek, and a groove provided in this cheek receives a spring defined in the other j-aw.

. Taking advantage of the favorable production conditions of the parted or separated carrying body, it can be furthermore provided that one part is provided at its end facing the point of the shuttle with a V-shaped longitudinal groove, and the other part with a nose or lug corresponding to the shape of the groove which in the assembled condition extends into the longitudinal groove. In this manner thread insertion conditions are provided which deviate the thread as little as possible from its direction determined by the point of the cops and the joining of yits end, conducts it in the space intermediate the parted carrying body, and which so closes the back beat path of the thread that it is prevented from escaping.

The insertion of the thread is facilitate-d in that the outer leg of the longitudinal groove is inclined inwardly and the start of the inclination as well as that of the outer surface of the nose are disposed symmetrically with respect to the vertical lcenter of the thread space or gap. The gneatest security against unthreading is obtained in that the inner leg of the longitudinal groove is elongated with respect to the outer leg, that in the assembled condition the intermediate space is covered up except for the `width of the thread insertion.

Brief'l description of the drawings Further details and features of the invention will become apparent from the following description of the drawings which show embodiments of the threading arrangements with thread tensioning means in accordance with the invention and in which- FIG. 1 is a plan view of the front end of the shuttle with the device incorporated therein,

FIG. 2 illustrates the device in a perspective and exploded view,

FIG. 3 shows an alternate embodiment of the device in a perspective and exploded View, and

FIG. 4 is a front View of the device in accordance with FIG. 3 as seen from the front end of the shuttle.

Description of the invention In the shuttle 1 a carrying :body 2 comprising parts 3 and 4 is mounted by means of a screw 5. To secure the relative positions a groove 7 is provided in the cheek 6 of part 3 and a spring 9 formed in the cheek 8 of part 4 which, in the embodiment shown, defines a bridge member between the parts. These parts 3 and 4 are held together by a shaft screw 10 which passes through a bore 11 in part 3 and threadedly engages the bore 12 in part 4 which presents a thread.

A recess 13 in cheek 6 receives a brake jaw 14, and a recess 15 in cheek 8 receives a brake jaw 16. Each of the brake jaws 14, 16 has a box-shaped member 14a, 16a,

respectively, which accommodates an elastic intermediate member 17, 18, respectively, which members project beyond the borders of the box-shaped brake jaws. The intermediate member 18 engages the bottom 15a of the recess 15, while intermediate member 17 rests against a pressure plate 19 that is engaged by a pin 20 of an adjusting screw 21 which is threaded into a threaded sleeve 22 in the shuttle 1 while its pin 20 projects through a bore 23 in part 3 and through the bottom 13a of recess 13. Recesses 13 and 1S also have enlarged portions 13b and 15b, respectively, at their entrances.

The weft thread 24 extends from a bobbin (not shown) between and through the brake jaws 14 and 16 and thence passes through two thread guides 25 and 26 which are lined with wear resistant material.

In the alternate embodiment part 3 is provided with a V-shaped groove 27 and part 4 with a wedge-shaped projection or nose 28. The outer leg of the V defining the groove is identified at 29 and the inner leg at 30. In the assembled condition a gap 31 and a thread path 32 are formed between parts 3 and 4.

Having now described my invention with reference to the embodiments illustrated in the drawings, I do not wish to be limited thereto, but what I desire to protect by Letters Patent of the United States is set forth in the appended claim.

-I claim:

1. Thread tensioning device with brake jaws for a weft thread shuttle of split construction comprising a carrying body made in two parts presenting opposite jaws, each of said two parts having a recess in its cheek, each disposed opposite the recess in the other part and each recess having an enlarged portion proximate'said cheek, said brake jaws each comprising a box-shaped member and an elastic intermediate member having a portion received in and encompassed by said box-shaped member, said elastic intermediate portion being received in and in engagement with said recess with a sliding fit, and said box-shaped member being loosely received in said enlarged portion of said recess to permit a iioating action.

References Cited UNITED STATES PATENTS 1,584,564 5/1926 Lance 139-217 2,990,856 7/ 1961 Villani et al 139-223 1,684,781 9/1928 Ricard 139-223 2,117,354 5/1938 Park 139-217 2,276,408 3/ 1942 Marcora 139-218 2,377,925 6/1945 Davdelin et al 139-223 2,607,371 8/1952 Wood 139-223 2,717,616 9/1955 Gosselin 139-223 FOREIGN PATENTS 1,127,229 8/ 1956 France.

524,468 4/ 1955 Italy.

153,699 5/1962 U.S.S.R.

413,594 7/ 1934 Great Britain.

MERVIN STEIN, Primary Examiner.

I. KEE CHI, Assistant Examiner' 

